Functional interaction of adenovirus E1A with holo-TFIID.
Functional interaction of adenovirus E1A with holo-TFIID.
复制标题
腺病毒 E1A 与 Holo-TFIID 的功能相互作用。
DOI：
10.1101/gad.7.9.1810
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发表时间：
1993
影响因子：
10.5
通讯作者：
Berk,AJ
中科院分区：
文献类型：
--
作者：
Boyer,TG;Berk,AJ
几种调节转录因子的激活结构域已被证明在体外直接结合TATA盒结合蛋白（TBP）。然而，TBP还必须与多个相关的多肽（称为TAF）相互作用，以使这些相同的激活剂刺激转录。这些发现提出了一个问题，即TBP如何同时与如此多的蛋白质（激活剂和TAF）相互作用。在这里，我们表明腺病毒大E1 A蛋白的激活结构域可以特异性且稳定地结合分离的holo-TFIID，即由TBP和TAF组成的多亚基蛋白复合物。因此，与E1 A相互作用的TBP的表面必须暴露在全息-TFIID复合物中。为了评估这种相互作用的功能意义，我们建立了一个响应E1 A激活结构域的体外转录系统。向该系统中添加过量的E1 A通过隔离E1 A激活所需的靶因子来抑制（压制）E1 A依赖性和E1 A非依赖性转录。从在该系统中共同重建E1 A响应性转录的组分活性中，单独的holo-TFIID能够单独逆转由过量E1 A介导的转录抑制，表明holo-TFIID是E1 A激活结构域的直接功能靶标。
The activation domains of several regulatory transcription factors have been shown to bind directly in vitro to the TATA box-binding protein (TBP). Yet TBP must also interact with multiple associated polypeptides, called TAFs, for these same activators to stimulate transcription. These findings raise the question of how TBP can interact with so many proteins, both activators and TAFs, simultaneously. Here, we show that the activation domain of the adenovirus large E1A protein can bind specifically and stably to isolated holo-TFIID, the multisubunit protein complex consisting of TBP plus TAFs. Consequently, the surface of TBP that interacts with E1A must be exposed in the holo-TFIID complex. To assess the functional significance of this interaction, we established an in vitro transcription system responsive to the E1A activation domain. The addition of excess E1A to this system inhibits (squelches) both E1A-dependent and E1A-independent transcription by sequestering a target factor required for E1A activation. From among the component activities that collectively reconstitute E1A-responsive transcription in this system, holo-TFIID alone is singularly capable of reversing the inhibition of transcription mediated by excess E1A, indicating that holo-TFIID is the direct functional target of the E1A activation domain.